It is relatively common to reinforce the seams between concrete floor slabs to prevent the slabs from heaving relative to each other at the seam under unstable loading conditions or temperature fluctuations. When reinforcement members are cast to extend across a seam between floor slabs, cracking and failure in the concrete may occur at the reinforcement member from horizontal movement between the slabs. To prevent such cracking, pockets or sleeves may be cast in one of the slabs, where plates or bars that extend across seams between concrete slabs and engage inside pockets or sleeves to allow some horizontal movement of the plates or bars.